2iR 3 / 2 (Tr —T1/2)
2.252. q — o,„_ =40 W/m 2 , where i = 3, d is the
9n"'"lclaNA JIM
effective diameter of helium atom.
2.253. X = 23 mm > 1, consequently, the gas is ultra-thin;
q = p (v) (t^2 — t^1 )I6T (7 —1) = 22 W/m^2 , where (v)
= 118RTInM, T = 1 /2 (T (^1) ± T2).
2.254. T = 7'^1 + 1nT( 2 - .112/TR In 10 Rri
2.255. T =T1+
1IRT2 1 —T 11 1R 2 ( R^1 r)
2.256. T = To (R 2 — r 2 ) iv/4x.
2.257. T = To + (R 2 — r 2 ) w/6x.
3.1. The ratio Fei/Fgr is equal to 4.10 42 and 1.10 36 respectively;
q/m = 0.86.10-10 C/kg.
3.2. About 2.10 16 N.
3.3. dq/dt = 3 / (^2) a 2neomg//.
3.4. T
-1/
qlq2
(F 17
V
(1TH-12) 2 ' r3— /714F2 •
3.5. AT— lq° 8naeo (^) r 2 •
3.6. E = 2.7i — 3.6j, E = 4.5 kV/m.
ql
'1(Izeo (12±,2)3/2
3.8. E=2312 6q 0 R2 — 0.10 kV/m.
3.9. l^ q
E—
43180
For r the strength E 4neos
(0+1 2
q
) 3 / 2
in the case of a point charge. Eniax= q for 1=r1-11I.
6 j/ 18^0 r^2
3.12. (a) 48 X:R ; (b) E— X^0 R^2 For xR the
460 (x 2 + R93/2 •
strength E— (^) 4n ePo x3' where p= nR 2 X 0.
3.13. (a) E=
n V
; (b) E= In both cases
4Eo r a 2 d-r 2 go (r2 —a 2 ) •
E— 4 ne q or2 for r >> a.
3.14.
ns •
E= X 1r5 The vector E is directed at the angle 45° to
4 oy
the thread.
3.15. (a)
4
n17
eoR
72- • (b) E O.
3.7. E-
as
3 q R2
3.10. E- 47Esox 4 •
3.11. F — (^) 43-EsoR (^) •